--- a/mobile/android/base/GeckoAppShell.java
+++ b/mobile/android/base/GeckoAppShell.java
@@ -1163,34 +1163,36 @@ public class GeckoAppShell
 
         if (action.equalsIgnoreCase(Intent.ACTION_SEND)) {
             Intent shareIntent = getShareIntent(context, targetURI, mimeType, title);
             return Intent.createChooser(shareIntent,
                                         context.getResources().getString(R.string.share_title)); 
         }
 
         final Uri uri = normalizeUriScheme(targetURI.indexOf(':') >= 0 ? Uri.parse(targetURI) : new Uri.Builder().scheme(targetURI).build());
-        if (mimeType.length() > 0) {
+        if (!TextUtils.isEmpty(mimeType)) {
             Intent intent = getIntentForActionString(action);
             intent.setDataAndType(uri, mimeType);
             return intent;
         }
 
         if (!isUriSafeForScheme(uri)) {
             return null;
         }
 
         final String scheme = uri.getScheme();
 
         // Compute our most likely intent, then check to see if there are any
         // custom handlers that would apply.
         // Start with the original URI. If we end up modifying it, we'll
         // overwrite it.
+        final String extension = MimeTypeMap.getFileExtensionFromUrl(targetURI);
+        final String mimeType2 = getMimeTypeFromExtension(extension);
         final Intent intent = getIntentForActionString(action);
-        intent.setData(uri);
+        intent.setDataAndType(uri, mimeType2);
 
         if ("vnd.youtube".equals(scheme) &&
             !hasHandlersForIntent(intent) &&
             !TextUtils.isEmpty(uri.getSchemeSpecificPart())) {
 
             // Return an intent with a URI that will open the YouTube page in the
             // current Fennec instance.
             final Class<?> c;